Potential of Chitosan-Based Basil Essential Oil Nanoparticles in Preventing Microbial Contamination of Beef

Background: Microbial contamination of fresh beef remains a major challenge in the meat industry, driving the need for effective natural preservation strategies that can extend shelf life while meeting consumer demand. Methods: Chitosan-based edible coatings enriched with free and nanoencapsulated Ocimum basilicum L. essential oil at concentrations of 0.25%, 0.5% and 1% were evaluated for their efficacy on fresh beef during 20 days of refrigerated storage. Microbiological parameters, including total bacterial count, lactic acid bacteria, psychrotrophic bacteria, and Pseudomonas spp., as well as physicochemical indicators such as pH and thiobarbituric acid reactive substances, were monitored at regular intervals throughout storage. Results: All active coatings significantly retarded microbial growth and lipid oxidation compared to the uncoated control (p < 0.05), with effects being concentration-dependent. Nanoencapsulation was achieved with an efficiency of 74%, and all formulations consistently showed better results compared to free essential oil coatings at equivalent concentrations. Application of a chitosan coating with 1% nanoencapsulated essential oil reduced total viable count by 1.5 log CFU/g and lactic acid bacteria by 0.7 log CFU/g, with the most pronounced effect observed for Pseudomonas spp. (1.9 log CFU/g reduction). In the same sample, MDA content remained below the threshold level until the end of storage. Additionally, sensory analysis indicated that the use of nanoparticles significantly improved the overall acceptability of the coated beef. Conclusions: These findings confirm that chitosan–basil nanoparticle coatings represent a promising natural alternative to conventional preservatives for improving microbiological safety and extending the shelf life of fresh beef.